appraisal vs estimation

appraisal and estimation both are nouns.

Word	Noun	Adjective	Verb	Adverb
appraisal	Yes	No	No	No
estimation	Yes	No	No	No

As nouns, estimation is a hypernym of appraisal; that is, estimation is a word with a broader meaning than appraisal:

appraisal: an expert estimation of the quality, quantity, and other characteristics of someone or something
estimation: a judgment of the qualities of something or somebody

Other hypernyms of appraisal include estimate.

As nouns, appraisal and estimation are synonyms defined as:

appraisal and estimation: a document appraising the value of something (as for insurance or taxation)

Other synonyms of appraisal include estimate.

appraisal (noun)	estimation (noun)
an expert estimation of the quality, quantity, and other characteristics of someone or something	a judgment of the qualities of something or somebody
the classification of someone or something with respect to its worth	an approximate calculation of quantity or degree or worth
a document appraising the value of something (as for insurance or taxation)	the respect with which a person is held
	a document appraising the value of something (as for insurance or taxation)